Circuit breaker



May 14, 1935. s. o. WILMS CIRCUIT BREAKER Filed Dec. 16, 1929 Patented my '14, 1935 CIRCUIT BREAKER Gustav 0. Wilms, Milwaukee, Wis., assignor, by mesne assignments, to Allen-Bradley Company, Milwaukee, Wis. consin a corporation of Wis- Application December 16, 1929, Serial No. 414,377

20 Claims. (C

This invention relates to thermally operable circuit breakers.

The circuit breaker to which the invention applies in particular has a self-opening switch, a latch secured in a fixed position by a fusible binder to hold the switch closed, and an electric heater to generate heat and fuse the binder.

Such a circuit breaker is disclosed in the co-pending application of Gustav O. Wilms, Serial No. 226,386, filed October 15, 1927, issued November 14th, 1933, as Patent No. 1,935,257 of which this application is a continuation as to matter common to both applications. i

An object of the invention is to provide means to open the switch independently of the thermally operated latch.

Another object is to provide a circuit breaker which may function as an overload circuit breaker and as a manually operable switch.

Another object is to providea circuit breaker which is simple in construction and which may be economically manufactured.

According to the invention, the circuit breaker has a catch to hold the switch closed, thermally operable means to release the catch and permit the switch to open, and manually operable means to release the catch independently of the thermally operable means.

A circuit breaker embodying the invention is shown in the accompanying drawing in which the views are as follows:

Fig. 1 is a top plan view with the top cover plate omitted.

Fig. 2 is a longitudinal section on the lineof 2-2 of Fig. 1.

Fig. 3 is a bottom p cover plate omitted.

The circuit breaker mechanism is arranged in and carried by a casing I having the top and bottom thereof closed by cover plates 2 and 8, respectively, which are removably attached to the casing I by bolts 4.

The casing I has electric terminals 5 and 6 arranged upon the outside and a pair of switch contacts I and 8 upon the inside of the rear wall thereof.

The terminal 5 is electrically connected to the switch contact I, and two binding posts 9 and III are arranged upon the inside of the casing I and electrically connected, respectively, to the contact 8 and the terminal 6.

The contacts I and 8 are normally bridged by a. movable contact. II which is carried by a plunger I2 having the head I 8 thereof formed of Ian view with the bottom insulating material and extending through the front wall of the casing I.

The plunger I2 has a central bore I4 to receive the end of a guide I5 which is fixed in the rear wall of the casing I and guides the plunger I2 as 5 the same is reciprocated.

The bore I4 is open at its inner end only and contains a spring I6 which abuts the end of the guide I5 and urges the plunger I2 outwardly to move the contact I I out of engagement with the contacts 1 and 8.

The contact II is held in engagement with the contacts I and 8 against the action of the spring I6 by a catch I! which is pivoted upon a pin I8 arranged in a support I9 carried by the casing I.

The catch I1 normally engages a lug 20 on the plunger I2 and is urged into engagement there-' with by a spring 2I which encircles the'pin I8 and has one of its ends in engagement with a lug .22 on the catch I1.

The catch I! has a tripping arm 23 connected thereto or formed integral therewith by means of which the catch may be disengaged from the lug 20 to permit the spring IE to move the contact II out of engagement with the contacts I and 8.

The circuit breaker may be operated manually by means of a plunger 24 which is adapted to engage the tripping arm 23 and has an insulating head 25 extending through the front wall of the casing I.

. The plunger 24 is urged outwardly by a coil spring 26 which normally holds it out of contact with the tripping arm 23 and is arranged between the head 25 and an abutment 21 carried by the casing I and preferably formed integral with the binding post I0.

Pressure exerted upon the head 25 causes the plunger 24 to move inwardly against the action of the spring 26 and swing the tripping arm 23 to disengage the catch H from the lug 20 and permit the spring It to move the contact II out of engagement with the contacts I and 8.

The catch I I may also be tripped by an operating lever 28 which is pivoted upon the pin I8 and provided with a flange 29 to engage the tripping arm 23.

The flange 29 is urged toward the'arm 28 to actuate the same by the spring 2|, the action of which is constrained by a pawl 30 carried by the lever 28 and engaging a tooth of a ratchet wheel 3|.

The pawl 38 is urged into engagement with the Q teeth of the ratchet wheel 3| by a spring 32 which may be a continuation of the spring 2|.

The ratchet wheel 3| is fixed by a fusible binder 33, such as solder, to a heat conducting spindle 34 which is secured in the support l9 and heat insulated therefrom by a bushing 35.

The heat conducting spindle 34 extends through the support |9 into close proximity with an electric heater 36 which is connected to the binding posts 9 and I0. 3

The electric circuit through the circuit breaker is from the binding post 5, contact I, contact I contact 8, binding post 9, heater 36, binding post I!) and terminal 6.

Heat generated by the heater 36 under the infiuence of an overload is transferred by radiation to the heat conductor 34 and conducted thereby to the binder 33.

An excessive overload, or a predetermined overload continuing for a predetermined period of time, will cause the heater 36 to generate sufficient heat to fuse the binder 33 and permit the spring 2| to rotate the ratchet wheel 3| and swing the lever 28 sufiiciently to trip the catch I! so that the spring l6 may open the circuit breaker. Specifically, the operation is as follows: When the fusible binder 33 melts and releases the ratchet wheel 3|, that portion of the spring 2| coiled about the pivot 32 and engaging the pawl 30 and bearing against the pivot l8 tends to collapse the pawl and the operating lever towards each other. However, because of the presence of the ratchet wheel 3| the pawl 3|)v cannot swing toward the lever 28 unless the pivot 32 moves in an arc about the center of the pivot 8. This is What takes place.

As a consequence of this motion of the lever 28, its flange or finger 29 through engagement with the arm 23 causes this arm to swing about the center of the pivot Hi to disengage the catch I! from the lug 20. While the drawing shows a single spring, namely the spring 2|, for moving the catch out of operative position, upon release of the ratchet wheel and also for maintaining the catch engaged with the lug 20, there are in effect two separate and independently acting springs, a single spring being used merely for convenience in manufacture and assembly.

The binder 33 hardens quickly after the circuit is broken and the circuit breaker may be closed by pressing the plunger head l3 inwardly, the lug 2|] moving the pawl 30 into engagement with the ratchet wheel 3| and the catch l1 automatically engaging the lug 2|] and holding the switch contacts in engagement.

An overload circuit breaker and a manually operable switch are thus provided in a single compact structure and the switch may be operated Without affecting or disturbing the overload mechanism.

The invention herein set forth is susceptible of various modifications without departing from the scope thereof as hereafter claimed.

The invention is hereby claimed as follows:

1. A circuit breaker comprising a self-opening switch, a support, a catch carried by said support to hold said switch closed, thermally operated means arranged upon one side of said support to trip said catch and permit said switch to open, an electric heater arranged upon the other side of said support and connected in circuit with said switch to generate heat to operate said means, and manually operated means to trip said catch independently of said thermally operated means.

2. A circuit breaker comprising a casing, a pair of fixed contacts carried thereby, a plunger reciprocable in said casing, a bridging contact carried by said plunger to engage said fixed contacts and connect the same in series, a spring urging said plunger away from said fixed contacts, a catch pivoted upon said casing and normally engaging said plunger to hold said bridging contact in engagement with said fixed contacts against the action of said spring, a heat conductor carried by said casing and heat insulated therefrom, a ratchet wheel fixed upon one part of said heat conductor by a fusible binder, spring operated means for tripping said catch normally engaging said ratchet wheel and constrained thereby from tripping said catch, an electric heater surrounding another part of said heat conductor to generate heat to fuse said binder and permit said means to trip said catch, and manually operated means to trip said catch independently of said spring operated means.

3. A circuit breaker comprising a casing, a pair of fixed contacts carried thereby, a plunger reciprocablein said casing; a bridging contact carried by said plunger to engage said fixed contacts and connect the same in series, a spring urging said plunger away from said fixed contacts, a catch pivoted upon said casing and normally engaging said plunger to hold said bridging contact in engagement with said fixed contacts against the action of said spring, a tripping arm connected to said catch, a heat conductor carried by said casing and heat insulated therefrom, a ratchet wheel fixed upon one part of said heat conductor by a fusible binder, spring operated means to engage said arm and trip said catch normally engaging said ratchet wheel and constrained thereby from tripping said catch, an electric heater surrounding another part of said heat conductor to generate heat to fuse said binder and permit said means to trip said catch, and manually operated means to engage said arm and trip said catch independently of said spring operated means. V

4. A circuit breaker comprising a casing, a. selfopening switch carried by said casing, a catch pivoted upon said casing and normally holding said switch closed, a tripping arm connected to said catch, a heat conductor carried by said casing and heat insulated therefrom, a ratchet wheel fixed upon one part of said heat conductor by a fusible binder, an actuating lever pivoted upon said casing, a spring to urge said lever against said arm and trip said catch, a pawl carried by 'said lever and normally engaging said ratchet-wheel to hold said lever against ,the action of said spring, an electric heater surrounding-another part of said heat conductor to generate heat to fuse said binder and permit said lever to trip said catch, and manually operated means to engage said arm and trip said catch independently of said lever.

5. A circuit breaker comprising a casing, a plunger switch arranged in said casing and spring-biased to open position, a catch pivoted upon said casing and normally holding said switch closed, a tripping arm connected to said catch, a heat conductor carried by said casing and heat insulated therefrom, a ratchet wheel fixed upon one part of said heat conductor by a fusible binder, an actuating lever pivoted upon said casing, a spring to urge said lever against said arm and trip said catch, a pawl carried by said lever and normally engaging said ratchet wheel to hold said lever against the action of said spring, an electric heater surrounding another part of said heat conductor to generate heat to fuse said binder and permit said lever to trip said catch, and a manually operable plunger to engage said arm and trip said catch independently of said lever.

6. A circuit breaker, comprising stationary switch contacts, a plunger movable axially toward and from said contacts,'a movable contact carried by said plunger, a spring urging said movable contact toward open position, acatch to hold said switch closed, spring actuated means to trip said catch, a latch held in position by a fusible binder and normally engaged by said means to prevent the same from tripping said catch, an electric heater connected in circuit with said switch to generate heat to use said binder and thereby release said spring actuated means to permit the same to trip said catch, and means to "trip said catch independent of said spring actuated means.

7. A circuit breaker, comprising stationary switch contacts, a plunger movable axially towardand from said contacts, a movable contact carried by said plunger, a spring urging said movable contact toward open position, a catch to hold said switch closed, spring actuated means to trip said catch, an abutment held in position by a fusible binder, a pawl carried by said means and normally engaging said abutment to prevent said means from tripping said catch, an electric heater connected in circuit with said switch 'to generate heat to fuse saidbinder and thereby release said spring actuated means to permit the same to P trip said catch, and means to trip said catch independent of said spring actuated means.

8. A circuit breaker, comprising a switch having its movable contact biased to-an initial position, a switch latch to retain said movable contact in a predetermined position away from its initial position, means to actuate said switch latch 'at will to release said movable contact, apivoted tripper to actuate said switch latch independent of the aforesaid means, a tripper latch formed by a pawl and ratchet wheel arranged to restrain said tripper from actuating said switch latch, a fusible binder retaining said ratchet wheel in a fixed position, and means to heat said binder and thereby release said tripper latch to enable said tripper to actuate said switch latch and thereby allow said movable contact to return to its initial position.

. 9. A circuit breaker, comprising a switch having its movable contact biased to an initial position, a switch latch to retain said movable contact in a predetermined position away from its initial position, means to actuate said switch latch at will to release said movable contact, a pivoted tripper to actuate said switch latch independent 01 the aforesaid means, tripper latch formed by a pawl and ratchet wheel arranged to restrain said tripper from actuating said switch latch, a fusible binder retaining said ratchet wheel in a fixed position, means .to heat said binder and thereby release said tripper latch to enable said tripper to actuate said switch latch and thereby allow said movable contact to return to its initial position, and means for resetting said tripper and reengaging said tripper latch. I

10. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said-movable conto release said tripper latch.

11. A circuit breaker, comprising the combination with an electric switch'provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a latch actuator arranged "to release said switch latch at will to open said switch, a pivotedtripper arranged to release said switch latch, a tripper latch arranged to retain said tripper from releasing said switch latch, and means responsive to predetermined electrical conditions to release said tripper latch.

12. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact inengagement with said stationary contact, a pivoted tripper arranged to release said switch latch, a tripper latch arranged to retain said tripper from releasing said .switch latch, means responsive to predetermined electrical conditions to release said tripper latch, and means operated by said switch actuator to return said tripper toits initial position and reengage said tripper latch.

13. A circuit'breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a latch actuator arranged to release said switch latch at will to open said switch, a pivoted tripper arranged to release said switch latch, a

said tripper latch, and means operated by said switch actuator to return said tripper to its initial position and reengage said tripper latch? 14. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, 01' a pivoted switch latch arranged to retain said movable contact in I engagement with said stationary contact, a pivoted tripper arranged to release said switch latch, a tripper latch arranged to retain said tripper from releasing said switch latch and having a pawl engaging a ratchet wheel retained from rotation by a i'usible'binder, and means responsive to predetermined electrical conditions to fusesaid binder and thereby release said tripper latch. I

15. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a pivoted tripper arranged to release said switch latch, a tripper latch arranged to retain said ing a pawl engaging a ratchet wheel retained from rotation by a fusible binder, means responsive to predetermined electrical conditions to fuse said binder and thereby release said tripper latch, and means operated by said switch actuator to return said tripper to its initial position and reengage said tripper latch.

16. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a latch actuator arranged to release said switch latch at will to open said switch, a pivoted tripper arranged to release said switch latch, a tripper latch arranged to retain said tripper from releasing said switch latch and having a pawl engaging a ratchet wheel retained from rotation by a fusible binder, and means responsive to predetermined electrical conditions to fuse said binder and thereby release said tripper latch.

17. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a latch actuator arranged to release said switch latch at will to open said switch, a pivoted tripper arranged to release said switch latch, a tripper latch arranged to retain said tripper from releasing said switch latch and having a pawl engaging a ratchet wheel retained from rotation by a fusible binder, means responsive to predetermined electrical conditions to fuse said binder and thereby release said tripper latch, and means operated by said switch actuator to return said tripper to its initial position and reengage said tripper latch.

18. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a pivoted tripper arranged to release said switch latch, and means responsive to predetermined electrical conditions to actuate said tripper to release said switch latch and thereby open said switch.

19. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a piv-' oted switch latch arranged to retain said movable contact in engagement with said stationary contact, a pivoted tripping lever arranged to release said switch latch, means to actuate said tripping lever to release said switch latch and thereby open said switch, a pawl and ratchet Wheel latch restraining said means from actuating said tripping lever and having its ratchet wheel retained in a fixed position by a fusible binder, and an electric heater arranged to fuse said binder upon the occurrence of predetermined electrical conditions and thereby release said means. 7

20. A circuit breaker, comprising the combination with an electric switch provided with a switch actuator and a movable contact actuatable by said switch actuator to engage a stationary contact and thereby close said switch, of a pivoted switch latch arranged to retain said movable contact in engagement with said stationary contact, a pivoted tripper arranged to engage and release said switch latch to open said switch, means to actuate said tripper to release said switch latch, a pawl and ratchet wheel latch restraining said means from actuating said tripper and having a fusible binder to retain its ratchet wheel from turning, and an electric heater arranged to heat and fuse said binder under abnormal electrical conditions.

GUSTAV O. WILMS. 

